1. Field of the Invention
The present invention relates to a real-time 3D display system realized by using holographic projection, which comprises a capturing device, a projection device, and a display for a real-time 3D image, and relates to a real-time 3D display method, a real-time 3D image capture method, a projection display method, and a display manufacturing method.
2. Related Art
Chinese Patent No. ZL200410022193.7 entitled “METHOD AND DEVICE FOR MAKING DIGITAL SPECKLE HOLOGRAM”, and Chinese Patent No. ZL200510022425.3 entitled “HOLOGRAPHIC PROJECTION SCREEN, AND MANUFACTURING METHOD, SYSTEM, AND APPLICATION THEREOF” are incorporated herein by reference in their entireties.
Since the beginning of the last century, scientists never stop the search for a proper method to solve the “3D imaging” problem. Although the practical applications of 3D cinemas and lens board 3D photos in the middle of the last century marked a certain breakthrough, human beings are still far away from effectively realizing the super dream of moving visual space, that is, vividly transferring and displaying 3D information of the nature. Common fatal defects of the prior art are as follows. The 3D sense is false (for example, the audience in the cinema sees completely the same image at different positions). The resolution requirements for the imaging quality are sacrificed for a limited subjective feeling of the 3D reality. The implementation process is complicated. Sometimes, special inconvenient glasses are required for viewing.
The invention of the holography marks the birth of a brand new human visual medium, which can naturally transfer and display visual information in a 3D manner. However, the holography is still far from color real-time holographic 3D visual space moving and displaying. The pulse holography, composite holographic 3D images, and the rainbow holography lead to holographic printing and packaging industries that are currently popular around the world, the core of which is to provide anti-counterfeiting representations used for anti-counterfeiting and authentication concerning security of files and brands. Digital holographic printing technologies brings forth a method more proper than the conventional technologies of computer-generated holograms (CGHs), and the complicated computing and coding is replaced by a more efficient holographic recording manner, thereby solving the problem of output difficulty dedicated to restoring the amplitudes and phases. However, the digital holography is so far still limited to the printing and displaying of holograms.
For the real-time 3D displaying, many solutions are proposed before and after the invention of the holography. However, none of the solutions is further developed due to the subjective visual processing manner of the issue and lack of proper theoretical support and experimental conditions.
Recently, with the development of the television (TV) information technologies and a clever application of a Spatial Light Modulator (SLM), a solution of a 3D holographic TV set is proposed for real-time 3D display. However, like the films and TV programs, all the methods use the effect of persistence of vision to realize 3D display by scanning and outputting spatial 3D information in a time-sharing manner, and therefore the TV set is not a real holographic TV set showing TV information in a holographic manner in the strict sense. Many methods proposes technologies such as directly reproducing a hologram written during power-on of the SLM to realize real-time 3D display, increasing a view angle, and realizing color display. Limited by a spatial bandwidth product of the conventional SLM, the methods are obviously far from practical application, and increase of the spatial bandwidth product is ultimately restricted by the so called Moore's Law manifesting integration capability of electronic chips. In an article “An updatable holographic three dimensional display”, recently published in Nature, Vol. 451/7 February 2008/694-698, a holographic TV set seems about to come true, but the practical application of the new holographic material is still inconceivable.
Practically, the nature is originally presented to humans in a real 3D manner. The 2D image information can only enable us to learn one side of an object, which to a great extent prevents the humans from learning the essence of the object comprehensively. It is a pity that although humans live in a 3D world, the human technologies still has to manifest the world in a 2D manner. For example, photos, films or TV programs form the main media of effectively transferring visual information of humans in the twentieth century. In the development of the science and technology in the 21st century, humans are bound to consider the approach of restoring a real 3D world being expressed by collecting massive image information according to a certain rule and reinterpreting and displaying the information in a real 3D manner, the approach of realizing 3D reconstruction and display of the massive image information, and the scientific relationship between the 2D image and the 3D display.